Support ring mounting for rotary radial piston pumps or motors



March 30, 1954 R HORTON 2,673,526

SUPPORT RING MOUNTING FOR ROTARY RADIAL PISTON PUMPS OR MOTORS FiledSept. 27, 1950 3 Sheets-Sheet 1 FIG. I. i

FIG. 2. FIG. 3. 5o 0 20 40 so so I00 e00 w 600 5 L 4/8 6 g 400 (L 0 200A/c I M: I O I 200 4 KS 52 3 400 m /4 5 m t 600 A? Q Y INVENTOR.

ROGER E HORTON QZWMW March 30, 1954 R, HORTON 2,673,526

SUPPORT RING MOUNTING FOR ROTARY RADIAL PISTON PUMPS OR MOTORS FiledSept. 27, 1950 3 Sheets-Sheet 2 F'IG.4. 55 5a 52 fi A INVENTOR ROGER F.HORTON R. F. HORTON RING MOUN March 30 1954 2,673,526 SUPPORT TING FORROTARY RADIAL PISTON PUMPS OR MOTORS 5 Sheets-Sheet 3 Filed Sept. 27,1950 mm W W 3 0% T H W N W i R MMNMI M N va MN: W 1% I l I I! N I m fixm m o W\ M.\ E Q R Hyena Patented Mar. 30, 1954 SUPPORT RING MOUNTINGFOR ROTARY RADIAL PISTON PUMPS OR. MOTORS Roger F. Horton, Hempstead, N.Y., assignor to United Aircraft Corporation, East Hartford,

Conn., a corporation of Delaware Application September 27, 1950, SerialNo. 187,030

8 Claims. 1:

This invention relates to improvements in rotary piston pumps or motorsandmore particularly in support ring mountings therefor. The inventionis concerned with pumps or motors in. which the stroke is regulated bymeans of a pivotally mounted track ring, and it is an object of theinvention to provide an improved pivotal mounting.

Another object of the invention is to penmitthe rotor to rotate freelyand concentrically on. the pintle, despite deformation of certain partsof the device due to the hydraulic pressures involved.

Further objects of the invention are to provide improved pressurecontrol for regulating the action of a variable delivery pump and toprovide a pressure control which does not interfere with theaccommodation of the-rotor to deflection of the pintle,

With these objects, and still other objects which will appear in thefollowing description in mind, apump embodying theinvention in apreferred form of embodiment will now be described, with reference tothe accompanying drawing and the features constituting theinventio-nwill then be pointed out in the appended claims.

-In thedrawing Figure 1 is a plan view of the pump", part of the coverplate being removed;

Figure 2 is moment diagram;

Figure 3 is a force diagram showing the forces producing the moments ofFigure 2;

t Figure 4 is a sectionon the line 4-4 of Figure 1, and on a largerscale; and

Figure 5 is a section on the line 55 of Figure 4. Y

The principal pump operating elements include the pintle A; on which therotor B rotates and in which the intake and discharge ports: are formed;the trackring C, against which the ends of the rotor pistons D- bear;and the support ring E, in which the track ring is rotatably carried.

Pintle A is bolted to and supported by an. end casting I (Figure 5),which in turn is fastened to the main housing casting 2 as by studs andnuts. Ihe fluid pumped; which usually will be oil, is suppliedthroughintake passage 3 and discharged through passage 4. Intake 3 leads to asuction port 5 and discharge connects to a discharge port 6 through.bores 1. These ports are formed inthe pintle A, as indicated, and areseparated, circumferentially, by lands 8 and 9 (Figs. 4 and 5).

The rotor B is formed, for convenience of manufacture, as amain body Inand a liner It fastened therein so that the two parts form a singlerigidstructure A pair of apertures 12 in the liner serves a. group ofthree pistons D reciprocably mounted in cylinder bores l3 in the bodyl.ll,,th.e pistons comprising the group being aligned in spacedrelation. along the; pump axis. Hydraulically, each pair of apertures I2 is equivadescribed in my said application lent to a single opening andthethree pistons D served thereby are equivalent to a single piston ofcorresponding area and stroke. As is apparent from Figure 4, a singlepiston of corresponding. area would subtencl an excessive arcand createdifiiculty in providing sufiicient rotor strength, or would require anincrease in the pintle diameter and overall pump size and weight. Thereare also considerations affecting the choice of pistonstroke, as pointedout hereinafter. Nine groups of pistons are provided, as indicated inFigure 4.

The track ring C includes a center member I5 to which are screwed a pairof end members 16 (Fig. 5) which include outwardly protrudingflangesforming annular L-shaped supports. The trackring is supported bymeans of anti-friction bearings 11, the inner races of which fit intomembers it as indicated and the outer races ofwhich are held in thesupport ring E by end caps l8 screwed onto the latter. The spacewith inthe track ring and around the pintle is sealedby sealing assemblies atl9 and 20 located adjacent the anti driVe and drive ends of the rotorrespectively. These sealing assemblies are described in detail in myapplication for scavenging System for Radial Piston Rotary Pumps filedas application Serial No. 217,340 on March 24, 1951, which matured intoPatent No. 2,653,542 dated September 29, 1953, and will not be describedin detail herein, it being sufiicient to note that the natureof theseals is such that they do not interfere with the movements of parts asdescribed below.

The rotor is driven through an Oldham coupling, having a. cup-shapedintermediate member 2-1: and driven by lugs 22 carried on a hollow shaft2-3 journaled in the drive end closure or casting 24 which is fastenedto the main casing 2 as by studs and nuts (Figure 1-). The hollow shaft23 is driven by drive-shaft 25 splined thereto and is pressed inwardlyby a spring 26. These elements as: well as other drive end structuresare fully for scavenging- Systems for Radial Piston Rotary Pumps, andwillnot be further described herein, since their specific form does notaffect the present invention. It is sufiicient'to note that thestructure is such as to permit the movement of parts as described below;

Ablock 38 is fixed in the lower part of support ring E and: is formedwith a concavity 3|, triangular in cross section, for cooperating with abearing edge or fulcrum 32 of the lower pivoted support.

For convenience of manufacture the pivot is formed of a pair of elements33, 34 positioned relative to each other by an formed in the lowerportion of element 33 and a. cooperating arcuate tongue. 34o protrudingfrom. the; element. 34, forming a, pivot. combination having the fulcrumedge 32 at its top and an arcuate slot 33w arcuate bearing surface 36between the elements 33, 34. The pivot 33, 34 sits in a bearing seatformed in the upper end of a screw plug 31. This plug is received in acorrespondingly threaded bore in the main casing 2. By turning the plug31 the height of fulcrum 32 may be adjusted, and the plug is held inadjusted position by a lock nut 38. An O-ring 39 may be utilized to sealagainst leakage at this point.

Pin which is integral with the element 34 extends downwardly into a bore40 in the plug 31. The pivot elements 33, 34 permit the support ring Eto be rocked about the fulcrum or knife edge 32 by the stroke controlmechanism described hereinafter. As the support ring is rocked about thefulcrum 32 the elements 33, 34 will form an absolutely rigid support inthe plane of the rocking. This is best seen by referring to Fig. 4 whenit is noted that the elements 33, 34 are keyed together against movementin this plane.

However, under load should the pintle deflect, the rotor, the track andsupport ring would also tend to tilt with respect to the axis ofrotation. Under such conditions while still supporting the ring evenlyon the entire length of fulcrum 32, the elements 33, 34 permit relativeadjustment therebetween on the arcuate surface 36 (Fig. 5) toaccommodate the aforementioned deflection.

The pivotal position of the support ring E eccentric to the pintle axisis regulated by a pressure control mechanism acting on a block fixed tothe top of the support ring. This mechanism is mounted on a framestructure 5| fastened to casting 2 by screws 52. It includes adjustablestop screws 53 provided with lock nuts 54, and acting against bevels 55at the top of block 50. These screws may be set so as to hold thesupport ring in a definite angular position on its fulcrum 32, whereconstant displacement operation is desired, or may be set, as shown, tolimit the movement of the support ring within a desired range.

The automatic pressure control mechanism comprises opposed knife edgemembers and BI thrusting against notches in the sides of block 50.Member 60 applies a force varying with the pump discharge pressure andmember 6| applies an adjustable spring force. The knife edge members 69,6! it should be noted as well as the block 50 have lateral dimension topermit relative lateral movement without becoming disengaged toaccommodate the above-mentioned support ring tilting.

A small hydraulic cylinder 62 is connected to discharge as by tubing 63(Figures 4 and 1) and operates hydraulic plunger 64. Link 65, pivotallyconnected to plunger 64 at 66, carries the knife edge 68. A roller 61,coaxial with the hinge axis of members 04 and 85, thrusts against a camsurface 68. Backlash is taken up by a small spring 69 when there is nopressure against the hydraulic plunger as when the device is notoperating. The parts are so dimensioned and positioned as to apply acounterclockwise movement to the support ring, which movement is adesired predetermined function of discharge pressure and support ringposition.

A compression spring 10 presses knife edge 6| against the block 50. Thespring pressure is adjusted by means of thrust member "H which isthreaded and carried in a threaded bore 12 in the frame 5|. Lock nut i3holds the member II in adjusted position. Tension spring 15 may be usedto offset certain forces in spring ID to ob-- tain certain types ofdischarge pressure-flow relationships. One end of this spring passesthrough an opening through the knife edge BI and hooks around a pin 16in the block 50 and the other end is attached to a screw threaded rod11. Rod 11 is carried in a threaded bore in the member II and is fixedin adjusted position by a lock nut 18.

The forces acting in the track ring are represented schematically inFigure 3, and the corresponding moments about the support ring fulcrumin Figure 2. In Figure 3 the arrows F3 and Fh represent the forcesapplied by the spring 10 and hydraulic cylinder 62 respectively in thepressure control. These-forces have a relatively large and substantiallyconstant moment arm about fulcrum 32 which moment arm is somewhat longerthan the track ring diameter. Arrow Fc represents the centrifugal forceresultant, acting in the direction indicated and having a substantiallyconstant moment arm which is equal to about half the support ringdiameter. Arrow Fp indicates the pressure resultant force due to thehydraulic pressure forcing the piston heads against the track ring. Thisforce has a variable moment arm about the fulcrum 32. No attempt is madein the figure to indicate the magnitudes of the forces involved, butonly their directions and moment arms.

In Figure 2 the abcissa represents the support ring eccentricity, ordistance between the pintle center 0 and support ring center 0 (Figure3), as percentage of maximum eccentricity for which the pressure controlmechanism is set. The 0rdinate represents moments about the fulcrum 32 iin inch pounds, for a pump chosen by way of example.

The lines Ms, Mh, Mp and Mc represent the moments corresponding to theforces Fs, etc. of Figure The spring moment Ms is shown as somewhat over700 inch pounds (clockwise) at zero eccentricity and drops linearly asthe eccentricity increases, in accordance with Hookes law. Thecentrifugal force moment Mc results from the fact that the pistons arerotating at constant angular velocity about the center 0 but are atdifferent distances from that center. The resultant pressure on thetrack ring thus increases with increasing eccentricity. Where theeccentricity is zero, this moment is likewise zero, and it increases toa value of nearly 200 inch pounds (clockwise) for maximum eccentricity.The moments Ms and Mc add up to the moment M1.

The pressure resultant moment MP is shown as zero for zero eccentricity,since in this position the force Fp is directed through the fulcrum 32.As the eccentricity increases, the moment arm increases and ateccentricity the moment Mp is shown as equalling 250 inch pounds(counterclockwise). The moment Mp re sults primarily from unbalancedpressures against the track ring of the pistons communicating withsuction and with discharge, and may also include frictional and othermoments which may be lumped together. The total counterclockwise moment,M2, equals the sum of the moments Mp and Mh.

For given speed of rotation, the moments Mh and Mp are functions ofdischarge pressure as well as displacement. Figure 2 assumes a constantdischarge pressure which may be, for example, 3,000 pounds per squareinch, and shows equal and opposite total moments M1 and M2 through arange of support ring eccentricity.

Assuming the mechanism is set for 3,000 pounds per square inch dischargepressure, and that an increased volumetric load is applied, as forexample, by opening the valve to a hydraulic actuator, the decrease inexternal hydraulic resist ance will tend to lower the dischargepressure. Both of the counterclockwise or anti-pumping moments Mp and Mhwill tend to drop correspondingly, so that clockwise or pumping momentM1 exceeds the anti-pumping moment M2. Support ring E accordingly movesclockwise to a position of greater eccentricity such that the increasedvolumetric rate of discharge into the lower external resistance raisesthe discharge pressure to the set value. Decreased load 0D- erates inthe reverse direction, so that the system automatically accommodates tovariations in the external load.

Th system, as described, is thus designed for constant pressure outputover a range of varying rates of delivery of the fluid. Where differentpressure delivery relationships are desired, the moment M2 may be made adifferent function of the discharge pressure and eccentricity by varyingthe form of the cam surface 68. Theoretical consideration of the form ofthis surface is unnecessar as it can be determined graphically for adesired moment in the usual manner for laying out cam profiles.

The flexibility of the system herein described is readily apparent inthat an arrangement is possible whereby the force Fh can be provided bya separate and independent system. Thus the independent system may beprovided with hydraulic pressure from a separate and conventional pumpWhile the herein described system would obtain pressure from the pump ofthis invention. Then by connecting the pressure control sensing line 63into the independent system the latter can control thepressure-discharge rate relationships of the system herein shown.

Although only one embodiment of this invention has been illustrated anddescribed herein, it will be evident that various changes andmodifications can be made in the shape and arrangement of the variousparts without departing from the scope of this novel concept.

What it is desired to obtain by Letters Patent is:

1. In a radial piston rotary pump having a pintle, a rotor rotatableabout the pintle axis, cylinders formed in said rotor and pistonsreciprocably carried in said cylinders and having respective headstherefor, a track ring surrounding and engaging the heads of the pistonsfor operating the same, a support ring for the track ring, and pivotmeans for permitting the support ring to swing transversely of thepintle axis and tilting with respect to said axis in the plane thereof,comprising a pivot element having a fulcrum supporting the support ringfor swinging transversely of said axis, a lower surface on said elementhaving a curve in one plane, a member having formed therein a seat toengage said curved surface, the face of said member opposite said seatbeing fiat transversely of said plane, and means to support said member.

2. In a radial piston rotary pump having a pintle, a rotor rotatablethereon, cylinders formed in said rotor and pistons reciprocably carriedin said cylinders and having respective heads therefor, a track ringsurrounding and engaging the heads of the pistons for operating thesame, a support ring surrounding the track ring, means rotatablymounting the track ring within the support ring, means pivoting thesupport ring for swinging transversely of the pintle axis including apivot element having a fulcrum supporting the support ring and having anarcuate lower surface, and a member having formed therein a seat forsaid arcuate surface, said pivot element and said seat including atongue and groove arrangement whereby slight relative movement betweenthe pivot element and said seat is permitted in the plane of the arc ofsaid arcuate surface.

3. A combination according to claim 2 comprising also a pin integralwith said seat member, a member adjustably fixed relative to said support ring and element, said last recited member having a bore receivingsaid pin for positioning said seat.

4. In a radial piston rotary pump having a track ring and a support ringtherefor, a support ring pivot comprising a pivot block having a fulcrumedge formed on one of its sides to engage a fulcrum seat formed in thesupport ring, an arcuate supporting surface formed on another side ofsaid pivot block, a member having an arcuate seat engaging said surface,and means for limiting movement of said surface with respect to saidseat.

5. A support ring pivot according to claim 4 including a fixed memberengaging said seat carrying member, and means for positioning said seatcarrying member with respect to said fixed member.

6. In a radial piston rotary pump having a track ring and a support ringtherefor, a support ring pivot comprising a two element pivot block, afulcrum edge engaging said support ring and carried by one of saidelements, an arcuate mating surface between said elements permittinglimited movement of said one element in the plane of the are, a fixedmember engaging the other of said elements, and means for positioningsaid other element with respect to said member.

7. A support ring pivot according to claim 6 wherein said positioningmeans comprises a pin carried by said other element and received by saidmember.

8. In a radial piston rotary pump having a pintle, a rotor rotatableabout the pintle axis, cylinders in said rotor and pistons carried insaid cylinders and having heads therefor, a track ring surrounding andengaging the heads of the pistons for operating the same, a support ringfor the track ring, a pivot engaging said support ring, means forpositioning the support ring for swinging transversely of said axisabout said pivot, said positioning means including a piston, a pair ofpivotally joined links one of which is operatively connected to saidpiston and the other of which engages said support ring, a rollercarried at the pivot of the links, and a cam surface engaging andcontrolling said roller.

ROGER F. HORTON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,778,902 Lampges Oct. 21, 1930 1,819,716 Mackenzie Aug. 18,1931 2,152,387 Porter Mar. 28, 1939 2,328,717 Glasner Sept. 7, 19432,386,459 Hautzenroeder Oct. 9, 1945 2,433,484 Roth Dec. 30, 19472,509,256 Sorensen Mar. 30, 1950 2,547,645 Horton Apr. 3, 1951 2,552,449Overbeke May 8, 1951 2,566,418 Horton Sept. 4, 1951 2,592,247 Coe Apr.8, 1952

